Nerve Terminal Motor Latency Testing Research Articles

ID:15782 Dorsal Root Ganglion Stimulation for Chronic Penile Pain and Fecal Urge With Incontinence

We present the case of a 58-year-old man who underwent DRG stimulation for chronic penile pain with unexpected resolution of fecal urge with incontinence. He initially presented with 8 months of penile pain, 10 years of fecal urgency, and 5 years of fecal incontinence. He had minimal benefit with pelvic physical therapy, Sitz baths, and medications via oral, transdermal, and rectal routes. Magnetic resonance imaging (MRI) lumbar neurogram was unremarkable, and MRI total spine was notable for severe right neuroforaminal narrowing at L4-5. Anorectal manometry and pudendal nerve terminal motor latency testing revealed signs of pelvic floor dyssynergia, including paradoxical puborectalis muscle contraction with Valsalva maneuver and altered rectal sensation. He had minimal relief with bilateral pudendal nerve blocks, left S2 and S3 selective nerve root blocks, and trigger point injections of the left puborectalis muscle.

Postpartum fecal incontinence. State of the problem

A review of the current national and foreign literature is devoted to epidemiology, risk factors, causes, diagnosis and modern treatment approaches for fecal incontinence (FI). Incidence of FI in early and delayed period after childbirth is 30% or more. At the same time, up to 87% of postpartum injuries of anal sphincter remain undiagnosed. Importantly, routine caesarean section does not reduce the risk of incontinence. In addition to typical complaints of spontaneous gas and stool, diagnosis of FI after childbirth includes transrectal ultrasound, MRI, anorectal manometry and pudendal nerve terminal motor latency testing. Survey of proctologists from different regions of Russia revealed a high demand from medical community for educational programs devoted to diagnosis, treatment and rehabilitation of patients with postpartum perineal injuries.

Stimulating electroneuromyography in the diagnosis of neurogenic disorders of the pelvic floor muscles

The article describes the technology for detecting and studying late phenomenon in stimulating electroneuromyography in order to objectively assess the state of innervation. The standard study of the motor response (M-response), Pudendal nerve terminal motor latency testing (PNTML), using the St. Mark's electrode from the external sphincter and pelvic floor muscles provides information only about efferent innervation at the distal part of the n. pudendus. At the same time, there are sparse reports in the literature on the study of the state of the mixed-fiber pudendal nerve along its entire length from its exit from the intervertebral foramen to the distal part using the St. Mark's electrode, the method is not clearly described, which, accordingly, causes the lack of application of the technique in clinical practice. The authors of this article cite the methodology for studying the late phenomenon in the form of a mixed feedback-reflex in stimulating electroneuromyography, describing the need to consistently use both methods of its registration.

Pudendal nerve terminal motor latency testing does not provide useful information in guiding therapy for fecal incontinence.

Pudendal nerve terminal motor latency (PNTML) testing is a standard recommendation for the evaluation of fecal incontinence. Its role in guiding therapy for fecal incontinence has been previously questioned. The aim of this study was to evaluate the relationship between PNTML testing and anorectal dysfunction. This was a retrospective analysis of data collected prospectively from patients who presented to a pelvic floor disorder center from 2007 to 2015. The relationship between PNTML (normal versus delayed) and anorectal manometry, fecal incontinence severity, and fecal incontinence-related quality of life scores was assessed using the Wilcoxon-Mann-Whitney test. Two hundred sixty-nine patients underwent PNTML testing, and 91.1% were female (N = 245) (median age 62.2years). Normal PNTML was seen in 234 (87.0%) patients. Among 268 patients who underwent anorectal manometry, delayed PNTML was only significantly associated with median maximum anal squeeze pressure (P = 0.04). Delayed PNTML was not associated with a decrease in median fecal incontinence severity or fecal incontinence-related quality of life scores (N = 99). PNTML was only associated with median maximum anal squeeze pressure, and it was not associated with patient-reported severity of symptoms of fecal incontinence, changes in quality of life attributable to fecal incontinence, median mean resting anal pressure, or median maximum resting anal pressure. PNTML testing may not be relevant to current therapeutic algorithms for fecal incontinence and its routine use should be questioned.

Anorectal physiologic evaluation of constipation.

Chronic constipation is a widespread problem which affects approximately 63 million people in North America alone. Although the majority of patients respond to changes in dietary fiber and water intake, as well as the judicious use of laxatives, a small portion will not and as a result, will be evaluated by gastroenterologists and colorectal surgeons. These patients most frequently have slow transit constipation, pelvic floor dysfunction, or some combination of the two. The physiologic evaluation of these patients comprises colonic transit studies, anorectal manometry, cinedefecography, electromyography, and pudendal nerve terminal motor latency testing. In this article, the authors describe the physiologic basis for these studies and review the techniques used in diagnosing these conditions.

Preoperative Anal Manometry Predicts Continence After Perineal Proctectomy for Rectal Prolapse

This study examines whether preoperative anal manometry and pudendal nerve terminal motor latency predict functional outcome after perineal proctectomy for rectal prolapse. All adult patients treated by perineal proctectomy for rectal prolapse from 1995 to 2004 were identified (N = 106). Forty-five patients underwent anal manometry and pudendal nerve terminal motor latency testing before proctectomy and they form the basis for this study. Perineal proctectomy with levatoroplasty (anterior 88.9 percent; posterior 75.6 percent) was performed in all patients, with a mean resection length of 10.4 cm. Four patients (8.9 percent) developed recurrent prolapse during a 44-month mean follow-up. Preoperative resting and maximal squeeze pressures were 34.2 +/- 18.3 and 60.4 +/- 30.5 mmHg, respectively. Pudendal nerve terminal motor latency testing was prolonged or undetectable in 55.6 percent of patients. Grade 2 or 3 fecal incontinence was reported by 77.8 percent of patients before surgery, and one-third had obstructed defecation. The overall prevalence of incontinence (77.8 vs. 35.6 percent, P < 0.0001) and constipation (33.3 vs. 6.7 percent, P = 0.003) decreased significantly after proctectomy. Patients with preoperative squeeze pressures >60 mmHg (n = 19) had improved postoperative fecal continence relative to those with lower pressures (incontinence rate, 10 vs. 54 percent; P = 0.004), despite having similar degrees of preoperative incontinence. Abnormalities of pudendal nerve function and mean resting pressures were not predictive of postoperative incontinence. Perineal proctectomy provides relief from rectal prolapse, with good intermediate term results. Preoperative anal manometry can predict fecal continence rates after proctectomy, because patients with maximal squeeze pressures >60 mmHg have significantly improved outcomes.

The Utility of Pudendal Nerve Terminal Motor Latencies in Idiopathic Incontinence

Pudendal nerve terminal motor latency testing has been used to test for pudendal neuropathy, but its value remains controversial. We sought to clarify the relationship of pudendal nerve terminal motor latency to sphincter pressure and level of continence in a cohort of patients with intact anal sphincters and normal pelvic floor anatomy. We reviewed 1,404 consecutive patients who were evaluated at our pelvic floor laboratory for fecal incontinence. From this group, 83 patients had intact anal sphincters on ultrasound and did not have internal or external rectal prolapse during defecography. These patients were evaluated by pudendal nerve terminal motor latency testing, a standardized questionnaire, and anorectal manometry, which measured resting and squeeze anal pressures. Incontinence scores were calculated by using the American Medical Systems Fecal Incontinence Score. Values were compared by using the Fisher's exact test and Wilcoxon's rank-sum test; and significance was assigned at the P < 0.05 level. 1) Using a 2.2-ms threshold, 28 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 12 percent bilaterally. 2) At a 2.4-ms threshold, 18 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 8 percent bilaterally. 3) Bilaterally prolonged pudendal nerve terminal motor latency was significantly associated with decreased maximum mean resting pressure and increased Fecal Incontinence Score, but not decreased maximum mean squeeze pressure, at both 2.2-ms and 2.4-ms thresholds. 4) Unilaterally prolonged pudendal nerve terminal motor latency was not associated with maximum mean resting pressure, maximum mean squeeze pressure, or fecal incontinence score at either threshold. The majority of incontinent patients with intact sphincters have normal pudendal nerve terminal motor latency. Bilaterally but not unilaterally prolonged pudendal nerve terminal motor latency is associated with poorer function and physiology in the incontinent patient with an intact sphincter.

Radio-frequency energy delivery to the anal canal for the treatment of fecal incontinence.

In this prospective study we investigated the feasibility, safety, and efficacy of radio-frequency energy delivery deep to the mucosa of the anal canal for the treatment of fecal incontinence. We studied ten patients with fecal incontinence of varying causes. All patients underwent anoscopy, anorectal manometry, endorectal ultrasound, and pudendal nerve terminal motor latency testing at baseline and six months. The Cleveland Clinic Florida scale for fecal incontinence (Wexner, 0-20), fecal incontinence-related quality of life score, and Short Form 36 were administered at baseline, 1, 2, 3, 6, and 12 months. Using conscious sedation and local anesthesia, we delivered temperature-controlled radio-frequency energy via an anoscopic device with multiple needle electrodes to create thermal lesions deep to the mucosa of the anal canal. Ten females (age, 55.9 +/- 9.2 years; range, 44-74) were enrolled and treated. Median discomfort by visual analog scale (0-10) was 3.8 during and 0.9 two hours after the procedure. Bleeding occurred in four patients (14-21 days after procedure), spontaneous resolution (n = 3) and anoscopic suture ligation (n = 1). At 12 months, the median Wexner score improved from 13.5 to 5 (P < 0.001), with 80 percent of patients considered responders. All parameters in the fecal incontinence-related quality of life were improved (lifestyle (from 2.3 to 3.4), coping (from 1.4 to 2.7), depression (from 2.2 to 3.5), and embarrassment (from 1.3 to 2.8); P < 0.05 for all parameters). Protective pad use was eliminated in five of the seven baseline users. At six months, there was a significant reduction in both initial and maximum tolerable rectal distention volumes. Anoscopy was normal at six months. Radio-frequency energy delivery to the anal canal for treatment of fecal incontinence is a new modality that, in this study group, safely improved Wexner and fecal incontinence-related quality of life scores, eliminated protective pad use in most patients, and improved patient quality of life.

Pudendal nerve terminal motor latency testing: assessing the educational learning curve: can we teach our own?

Pudendal nerve terminal motor latency testing is useful as a diagnostic tool in fecal incontinence. It has also been used as a predictive factor in sphincteroplasty repairs. The technique is seldom taught and mastered in colorectal training programs. The purpose of this study was to assess a learning curve for teaching this procedure. The student was a formally trained colorectal surgeon with no pudendal nerve terminal motor latency experience; the instructor has performed more than 3,000 pudendal nerve terminal motor latency studies. Fifty consecutive patients had manometry and pudendal nerve terminal motor latency testing. Both the student and instructor performed pudendal nerve terminal motor latency in a sequential fashion. Variables collected included pudendal nerve terminal motor latency, completion of test, time to complete test, and accuracy of the test. Variables were analyzed with paired t-test and chi-squared analysis. The study group included 41 female and 9 male patients. The average age of the patients was 53 years. Bowel complaints included constipation in 16 and incontinence in 34 patients. Data were analyzed in their entirety and at ten-patient intervals. The student tended to record longer latencies (P < 0.001). This led to false-positive rates of 23 and 21 percent, respectively, for left and right pudendal nerve terminal motor latency. On average, the time to complete the procedure was three times longer for the student than for the instructor (P < 0.001). At ten-patient intervals, the pudendal nerve terminal motor latency difference between the two groups disappeared at the 41-to-50-patient mark. Given the proper learning environment, pudendal nerve terminal motor latency testing can be mastered in a relatively short period. On the basis of this study, our estimation is 40 patients are required for a student to master this technique. The novice examiner can expect false-positive results early in the learning curve, and these should be validated accordingly.

Incontinence after lateral internal sphincterotomy: anatomic and functional evaluation.

This study was designed to evaluate the anatomic and functional consequences of lateral internal sphincterotomy in patients who developed anal incontinence and in matched controls. The study includes 13 patients with anal incontinence after lateral internal sphincterotomy and 13 controls who underwent the same operation and were continent and satisfied with the results of the procedure. Patients underwent clinical evaluation, anorectal manometry, pudendal nerve terminal motor latency testing, and endoanal ultrasonography. Sphincterotomies were longer in incontinent patients (75 vs. 57 percent), but the resting pressure and length of the high-pressure zone were not different between groups. Surprisingly, maximum voluntary contraction was higher in incontinent patients than in continent controls (136 vs. 100 mmHg). Rectal sensation and pudendal nerve terminal motor latency were similar in both groups. The defect in the internal sphincter was wider in incontinent patients than in continent controls (17.3 vs. 14.4 mm), but these differences were not statistically significant. The thickness of the internal sphincter measured by endoanal ultrasound was identical in both groups, but the external sphincter was thinner in incontinent patients both at the site of the sphincterotomy (6.8 vs. 8.1 mm) and in the posterior midline (7.1 vs. 8.6 mm). Anal incontinence after lateral internal sphincterotomy is directly related to the length of the sphincterotomy. Whether secondary to preoperative sphincter abnormality or the result of lateral internal sphincterotomy, the external sphincter is thinner in incontinent patients than in continent controls.